You don't need a vacuum gauge to test the vacuum advance unit. Just suck
on the end of the hose and see if the distributor breaker plate moves. If
you suck in a lot of nasty-tasting air, it has a leak. Simple, eh?
Dave Wood had this to say:
>Dan,
>
>I have a 72 and have also removed the air pump, gulp valve and plugged all
>the holes. I don't have a problem like you mention, but in the past have
>had my intake manifold work loose, which caused a leak and made it die and
>run rough. The other problem that you might have is a leaky vacuum advance.
>Mine leaks a bit and I haven't replaced it yet. If you have a vacuum tester
>(makes a vacuum, not a gauge) you can check to see if the vacuum advance
>will hold a vacuum. There is also the possibility that the plug(s) at the
>ends of the intake manifold have developed a leak. I blew one completely
>out once after I had set my valves and unknowingly stripped one of the nuts.
>The nut loosened up and a large backfire blew the end plug right out onto
>the firewall. Fortunately I was only a couple of blocks from home. Thought
>I had really done it that time, but no harm was done.
>
>When you are done with yours, come fix mine.
>
>Dave 72 B
>----- Original Message -----
>From: "Dan Dougherty Sr." <globalrc@mindspring.com>
>To: "MGS" <mgs@autox.team.net>
>Sent: Wednesday, November 29, 2000 12:55 PM
>Subject: 72 MGB-carbs, HIF type
>
>
>> The patient is a 72 MGB with HIF carbs, most of the pollution is disabled,
>> carbs rebuilt. Runs great, idles all day at a steady pace.....unless you
>> drop the revs quickly. THE IT DIES....like when you come to a stop.
>Restarts
>> easily. Manifold vacuum fluctuates on a gauge. No vacuum leaks anywhere I
>> can detect....been all over with spray. Any ideas? This one is bugging me.
>> Yes, we soldered the butterflys. Dan
>
--
Max Heim
'66 MGB GHN3L76149
If you're near Mountain View, CA,
it's the red one with the silver bootlid.
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